Petroleum cokes are products obtained by thermal cracking of heavy petroleum oils. Delayed coking, fluid coking, contact coking, and flexi coking are known in the art as processes for manufacturing petroleum cokes. Among the petroleum cokes manufactured by these processes, there are green cokes containing about 10% of volatile matters and calcined cokes which are obtained by calcining the green cokes at a high temperature to remove the volatile matters and to effect crystallization. Green cokes are mainly used as fuels. Among calcined cokes, those containing only a small amount of impurities and possessing high crystallinity are used as raw materials for manufacturing electrodes and carbonaceous materials.
Petroleum cokes have a higher heating value and contain less ashes than coal, but their ignitability is worse than coal. Since petroleum cokes are inexpensive, they are used as fuels for boilers, calcination of cement, and the like. Petroleum cokes with better ignitability when burning are thus desired. Petroleum cokes are dried and then pulverized prior to use into particles or powders with diameters of 200 mesh or smaller. Since the pulverization consumes a significant energy, petroleum cokes which can be easily pulverized are desired.
In addition, development of a technology to increase the yield of cracked oil in the thermal cracking of heavy petroleum oils has been desired.